astronomik - Planet IR Pro 742 1.25 inch 742 Planet

These new filters serve particularly the needs of the digital photographer imaging the solar system with electronic cameras or
Webcams (with IR-block filter removed) at long-focus telescopes.

The Astronomik planet IR pro CCD filter offers two main advantages:

   1. The filter passes only light within a range, that makes seeing become much lesser apparent than in the visual. In other
words: The picture becomes substantially steadier and thus also sharper in large telescopes.
   2. The filter is particularly useful for Mars CCD photography, because it opens at wavelengths, in which the surface details
show the highest contrast. 

Further advantages to the well-known RG filters from Schott:

    * better suppression of seeing as with Schott RG 665
    * steeper flanks (shorter exposure times)
    * multi-coated surface (better contrast)
    * optical thickness identically to other Astronomik filters (parfocal)
    * transmission adjusted for perfect use with amateur telescopes 

Why two different kinds of filters?

Solving the problem of decreasing optical resolution at higher Wavelengths was the main goal of the Astronomik team. So you are
able to make use of the better imaging quality caused by lower seeing effects. Besides this the nearly unpredictable near IR
sensitivity of most CCD and CMOS Sensors gave this issue a higher complexity. Using the results of a number of different tests
made by the team, confirmed by amateur experiences throughout the country, an optimal filter transmission curve could be
determined.

The 742 filter is designed for telescopes of smaller diameter. At this wavelengths most electronic cameras have still almost
their full efficiency. The majority of wavelengths troubled by seeing effects, is blocked.

The 807 filter is perfect for telescopes starting at 8 inch diameter. At this wavelengths most electronic cameras are less
sensitive. This effect is compensated by the larger aperture. But here however the seeing becomes much lesser apparent than with
the shorter-wave passing filter.

Facts:	
Main application 	For planetary and lunar photography these filters block the whole visual light. The pass the near IR where the
seeing is much better than at visual wavelengths. You'll get better images. Especially for mars these filters enhance the part of
the spectrum where dark and bright details have maximum contrast.
visual observation 	not useful
classical photography 	not useful
CCD-photography 	The filter is optimized for telescopes with more than 5 inch (~12,5cm) diameter. Use it with a webcam or video
camera without a IR-blocker ! The focal ratio for optimum results is f/25 .... f/40
Main parameters
 Transmission up to 98 %
 Blocking at 400 - 720 nm
 Transmission >95 % above 760nm

    * Transmission of more than 98% in the near IR
    * Extreme steep flank at 742nm
    * completely resistant against high humidity and scratches
    * highest optical quality on the market